John 13:17

These are obvious first principles in Christian discipleship, but the mere knowledge of them is not enough: εἰ ταῦτα οἴδατε, μακάριοί ἐστε ἐὰν ποιῆτε αὐτά. ταῦτα refers to what Jesus had just declared to be the significance of His action. εἰ οἴδατε, “if ye know,” as you do know; ἐὰν ποιῆτε, a supposition. “The knowing is objectively granted, the doing subjectively conditioned.” Meyer. On the double protasis see Burton, 268. μακάριοι is usually translated “blessed,” Matthew 5:3; John 20:29, and should be so here.